The present invention relates to semiconductor manufacturing facilities and, more particularly, to a semiconductor manufacturing facility having a heat recovery apparatus, which recovers heat generated by semiconductor manufacturing equipment.
In a semiconductor manufacturing plant, boilers and refrigerating machines are installed so as to serve as cold heat sources for air conditioning. In order to attempt energy conservation in the semiconductor manufacturing plant, it is required to reduce operation loads of the boilers and the refrigerating machines. For example, it is considered to use a method of saving a power consumed by a refrigerating machine by reducing a load to the refrigerating machine, which supplies a refrigerating medium to a dry coil, by reducing an amount of air supplied to a clean room or reducing an amount of air circulating in the clean room so as to reduce an amount of heat removed by the dry coil to cool the air circulating in the clean room. However, this method has a problem in that the temperature of the clean room cannot be adjusted in a case in which the temperature of the clean room is increased due to heat generated by semiconductor manufacturing equipment.
In the conventional class 10 clean room (particle diameter of 0.1 xcexcm), the number of circulations is 100 times per one hour. The reason for such a large number of circulations is not only to remove dust but also to maintain the temperature of the clean room at 23xc2x0 C. That is, it is necessary to remove heat by the heat exchange in the dry coil. If the number of times of the circulation is reduced, the temperature fluctuation in the clean room may not be controlled under certain operating conditions of the semiconductor manufacturing apparatus. As a result, there also is a problem in that an yield rate of the products is decreased since the dimensional deviation of machining is increased due to a temperature change of the semiconductor manufacturing equipment which needs a temperature control due to its property.
Accordingly, in view of saving the air conditioning energy in the semiconductor manufacturing plant, it is preferable for the conventional facility to increase the setting temperature of the clean room as high as possible. However, an environment of a temperature exceeding 23xc2x0 C. is an operating environment in which a worker wearing clean clothes in the clean room feels hot. Additionally, natrium or ammonium is generated due to sweating of the worker, which may deteriorate the working environment. Accordingly, in view of the working environment, it is not preferable to increase the setting temperature of the clean room to a temperature above 23xc2x0 C.
In view of the above mentioned, it is said that the method of reducing the number of times of circulation in the clean room or a method of increasing the setting temperature of the clean room is not a decisive plan to achieve the energy saving.
A description will now be given of a conventional apparatus for cooling the semiconductor manufacturing equipment. FIG. 1A is a perspective view of a single coil cooing pipe 10 conventionally used to cool a heating furnace (specifically, a heat generating part thereof) of the semiconductor manufacturing equipment. FIG. 1B is a front view of the cooling pipe 10. The cooling pipe 10 is wound on the periphery of the semiconductor manufacturing equipment, and cooling water is supplied to a lower cooling water inlet port 11. The cooling water flows through a coil portion, and exit from an upper cooling water outlet port 12. Release of heat to outside (inside the clean room) is suppressed by the cooling water recovering the heat of the semiconductor manufacturing equipment.
The temperature of the cooling water supplied to the cooling water inlet port 11 is maintained at about 23xc2x0 C., which is a setting temperature of a clean room so that dew formation does not occur. The temperature of the cooling water exiting from the cooling water outlet port 12 normally ranges from about 25xc2x0 C. to 28xc2x0 C. although the temperature varies according to the operating conditions. That is, a temperature difference between the cooling water inlet port 11 and the outlet port 12 is about 5xc2x0 C.
A description will now be given, with reference to FIG. 2, of a cooling system of the cooling water supplied to the cooling pipe 10. Cold water of about 6xc2x0 C., which is cooled by a refrigerating machine 101, is temporarily stored in a cold-water tank 102, and is delivered to a heat exchanger 103. The cold water delivered to the heat exchanger 103 cools the cooling water to be supplied to the coil-type cooling pipe 10, and, thereafter, returned to the cold-water tank 102. On the other hand, the cooling water stored in a buffer tank 104, which has a temperature higher than 23xc2x0 C., is delivered to the heat exchanger 103 by a water pump 105, and is cooled to the temperature of 23xc2x0 C. by exchanging heat with the cold water of 6xc2x0 C. The cooling water enters the inlet port 11 of the coil-type cooling pipe 10, passes through the cooling pipe 10 and exits from the outlet port 12 so as to be returned to the buffer tank 104. It should be noted that, in FIG. 2, 106 indicates a cooling tower, 107 indicates a temperature sensor, and 108-110 indicate water pumps.
In the above-mentioned cooling apparatus, since the temperature at the outlet port of the cooling pipe 10 is as low as below 30xc2x0 C., a temperature difference between the air or water with which heat is exchanged is small. Accordingly, the heat exchange efficiency is low, and the cooling water was not able be used for heat recovery. Additionally, since the temperature of the cooling water supplied to the cooling pipe 10 is set to the setting temperature of 23xc2x0 C. of the clean room, the cooling water of a separate system must be controlled to about 23xc2x0 C. by heat exchange by the heat exchanger 103 using the cold water of about 6xc2x0 C. produced by the refrigerating machine 101. Accordingly, the refrigerating machine 101 and the heat exchanger 103 are needed, thereby increasing a thermal energy loss, and, additionally, since two cooling water delivery lines are needed, a separate water pump must be provided to each of the lines. As a result, there is a problem in that an area occupied by the facility is increased, and a facility equipment cost is increased.
In the above-mentioned cooling system, an amount Q of heat absorbed by the cooling water from the heat source (semiconductor manufacturing apparatus 1) is represented by the following equation (1), where amount of cooling water is W, specific heat is Cw, inlet temperature is Ti, outlet temperature is TO and temperature difference between inlet and outlet is xcex94T.
xe2x80x83Q=Wxc2x7Cwxc2x7(TOxe2x88x92Ti)=Wxc2x7Cwxc2x7xcex94Txe2x80x83xe2x80x83(1)
In the equation (1), since the specific heat Cw s constant and the temperature difference xcex94T is as small s about 5xc2x0 C., the amount W of cooling water must be increased so as to increase the amount Q of heat absorbed by the cooling water. Accordingly, a large amount of cooling water is needed, and there is a problem in that a power cost of the pump is increased. Additionally, since the cooling water is supplied to the cooling water coil 10 by a full operation of the pump even in a steady state, an insufficient cooling occurs when the temperature at the outlet port 12 is rapidly increases due to a rapid increase of the load during the operation of the apparatus.
Additionally, a micro vibration is generated due to an inevitable increase in the amount of cooling water flowing through a main water delivery pipe due to a large amount of cooling water flowing through the cooling pipe. If the generated micro vibration propagates the clean room structure, which is a support member of a water delivery main pipe, a bad influence is exerted on an exposure machine and a scanning electron microscope, which are sensitive to a vibration are installed in a process area. In addition to those problems, there also is a problem in that rust or corrosion occurs in the cooling pipe, the pipe, the pump and the heat exchanger through which the cooling water flows.
It is an object of the present invention to provide an improved and useful semiconductor manufacturing facility in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to reduce energy consumption of a semiconductor manufacturing plant as a whole by effectively using the heat generated by semiconductor manufacturing equipment for air conditioning of the semiconductor manufacturing plant or heating materials to be used.
It is another object of the present invention to reduce an amount of cooling water used for the semiconductor manufacturing equipment so as to attempt energy saving of a pump power.
It is a further object of the present invention to simplify a cooling facility of the cooling water used for the semiconductor manufacturing equipment.
In order to achieve the above-mentioned objects, there is provided according to the present invention a semiconductor manufacturing facility characterized by:
semiconductor manufacturing equipment;
a cooling jacket unit which cools the semiconductor manufacturing equipment;
a heat recovery part which recovers heat from warmed exhaust water, which is cooling water absorbing heat passing through the cooling jacket unit and being released from said semiconductor manufacturing equipment; and
a supply pipe which supplies the warmed exhaust water, which has recovers heat in said heat recovery part, to said cooling jacket unit,
wherein the heat recovered by the heat recovery part is utilized as a heat source used in a semiconductor manufacturing plant.
According to the present invention, the energy consumed by the semiconductor manufacturing plant can be saved since the heat generated by the semiconductor manufacturing equipment is reused as a heat source used in the semiconductor manufacturing plant by using the cooling water as a medium. In the present invention, it is preferable to make a structure which is provided with a temperature detecting part detecting a temperature of a cooling water outlet port of the cooling jacket unit and a flow control part controlling a flow of the cooling water flowing through the cooling jacket unit so that a temperature detection value by temperature detecting part becomes equal to a setting temperature. Additionally, a structure may be used which structure is provided with a bypass passage connecting between an inlet port and an outlet port of the cooling jacket unit so as to allow a flow from the outlet port toward the inlet port by bypassing the cooling jacket unit and a flow control part provided to the bypass passage so as to control an amount of the cooling water. Further, a structure may be used which structure is provided with detecting means for detecting a temperature difference between the inlet port and the outlet port of the cooling jacket unit, and wherein an amount of the cooling water flowing through the cooling jacket unit via the flow control part provided to the bypass passage in accordance with the temperature difference detected by the detecting means. The structure in which the bypass passage is provided is particularly effective when the cooling jacket unit is a single pipe coil. Additionally, a heat exchanger for cooling the warmed exhaust water flowing through the supply pipe may be provided so as to produce the cooling water, and the cooling water exiting from the heat exchanger may be supplied to the cooling jacket unit.
Additionally, it is preferable that the cooling jacket unit has a structure having a so-called double jacket that comprises: an inner fluid passage formed so as to surround a periphery of a heat generating part of the semiconductor manufacturing equipment and having an outlet port of the cooling water; an outer fluid passage communicated with said inner fluid passage and having an inlet port of the cooling water, the outer fluid passage being formed so as to surround a periphery of the inner fluid passage and is capable of exchanging heat with the cooling water in the inner fluid passage. According to the above-mentioned structure, since the cooling water in the outer fluid passage is warmed by the cooling water in the inner fluid passage, the temperature difference between the inlet port and the outlet port of the cooling jacket unit can be increased while the temperature difference on the side of the semiconductor manufacturing equipment is suppressed to be small, thereby reducing the amount of the cooling water.
Specifically, a temperature of the cooling water supplied to the cooling jacket unit is equal to or higher than 10xc2x0 C. and less than 45xc2x0 C.; a temperature flowing out of the cooling jacket unit is less than 98xc2x0 C.; and a temperature difference between the cooling water to be supplied to the cooling jacket unit and the cooling water flowing out of the cooling jacket unit is set equal to or greater than 35xc2x0 C. It should be noted that the cooling water supplied to the cooling jacket unit preferably be deoxidized and a reducing agent is dissolved therein. According to this, a metal part such as a pipe can be prevented from being corroded. For example, hydrogen is used as the reducing agent. An amount of the dissolved hydrogen relative to the cooing water is preferably equal to or greater than 0.4 ppm. Additionally, it is preferable that surfaces of the cooling jacket unit and at least a part of an outlet port pipe from the outlet port of the cooling jacket unit to a part contacting air in a clean room are preferably covered by a heat insulator, which does not generate a gaseous contaminant.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompany drawings.